Plastic barge for cryogenic service



Dec. 6, 1966 H. R. PRATT 3,289,624

PLASTIC BARGE FOR CRYOGENIG SERVICE Filed Jan. 18, 1965 n N. Fi '?r H/-I4 I /l4 up '0 FBGE H2 mm; 10R,

HAROLD R PRATT WHELAN, CHASAN, LITTON, MARX 8 WRIGHT ATTORNEYS UnitedStates Patent 3,289,624 PLASTIC BARGE FOR CRYOGENIC SERVICE Harold- R.Pratt, Ridgewood, N.J., assignor to Esso Research and EngineeringCompany, a corporation of Delaware Filed Jan. 18, 1965, Ser. No. 426,2713 Claims. (Cl. 114-74) The present invention relates to lbargeconstructions, and more particularly to barges adapted to transportcryogenic cargoes, such as liquefied natural gases at atmosphericpressures.

It has been established that the transportation of gases, such asnitrogen, methane, and the like, to remote locations may best and mostefiiciently be accomplished by reducing the volume of the gas throughits conversion into the liquid state. Such a conversion enables thestorage volume requirements to be greatly reduced (approximatelysix-hundredfold for a given quantity of methane gas, for example) and,as should be appreciated, enables the most efiicient transfer of the gasto a remote area.

In order to transfer liquefied gas in a practical and economical mannerin relatively large volumes, it is necessary to store the liquefied gasat approximately atmospheric pressure, since large vessels "built towithstand superatmospheric pressures would be impractical, if notimpossible to construct for use in or on barges, seagoing tankers or thelike. Moreover, liquefied gases maintained at atmospheric pressures haveextremely low vaporization points, ranging from about 435 F. forliquefied hydrogen, to -28 F. for liquefied ammonia, and these unusuallylow temperatures of the liquids present certain problems. Specifically,the vessels must be sufficiently thermally insulated to be capable ofpreventing heat losses which would lead to subsequent vaporization ofthe stored liquefied gas. They also must be of sufficient strength inthe cold condition to withstand the often substantial internal stressesthat may be induced herein by the large temperature gradients throughits walls.

Heretofore, the proposed solutions to the problem of safely and reliablytransporting liquefied gases at cryogenic temperatures and atmosphericpressure have utilized separately insulated liquid and gas impermeablecontainers which are, themselves, independently, integrally, orotherwise installed in otherwise general-1y conventional ships orbarges. Furthermore, in the interest of safety and in conformance withmaritime regulations, the conventional steel vessel structure, which issubject to damaging embrittlement by leakage of the cryogenic liquefiedgas cargo, has been separated from the supercooled cargo by more thanone liquid and gas impermeable barrier.

The present invention represents an entirely new approach and animproved solution to the problems associated with the marinetarnsportation of liquefied gases at cryogenic temperatures.Specifically, the ship, the thermal insulation, and the cryogeniccontainer are fabricated as one and the same from special steppedplastic structural members or panels, made in accordance with generalprecepts set forth in detail in my copending application Serial No.394,287, filed September 3, 1964, for Insulation System. In accordancewith the invention, the plastic panels possess suflicient insulating andstrength properties to prevent vaporization of the liquefied gas and toretain the integrity, seaworthiness, and cargo-impermeability of theship.

The insulated cryogenic container of the invention is built in thegeneral form of a closed barge, using a series of stepped, interlockingplastic panels. The panels themselves are formed of fiberglassreinforced polyester resin shells filled With foamed polyurethane. Inthe barge of the invention, each of the joints between adjacent,

matingly stepped panels is made fast and liquid-tight by means such asan epoxy adhesive.

As will be appreciated, the new barge, as a single struc ture, functionsin the multiple capacities of what heretofore required several distinctstructural entities, i.e., a container system, an insulating system, anda ship, which were themselves interrelated by sometimes complicatedmounting systems to accommodate difierential rates of expansion.Furthermore, since the barge is constructed entirely from plastic, theelimination of steel from the structure obviates the requirement foradditional or secondary barriers and/ or insulation to protect the steelfrom the cryogenic cargo. Accordingly, a multiple-functioning barge maybe constructed in accordance with the invention with a significantsavings in material and labor costs in comparison with conventionalmarine transportation systems for cryogenic cargoes.

For a more complete understanding of these and other attendantadvantages of the present invention, reference should be made to thefollowing detailed description taken in conjunction with theaccompanying drawing in which:

FIG. 1 is a longitudinal cross-sectional View of a new and improvedbarge embodying the inventive concepts;

FIG. 2 is a plan view of the barge shown in FIG. 1;

FIG. 3 is an enlarged cross-sectional view of the new and improved bargetaken along line 3-3 of FIG. 1;

FIG. 4 is an enlarged, fragmentary, cross-sectional view of the bargetaken along line 44 of FIG. 3; and

FIG. 5 is a further enlarged, fragmentary, cross-sectional view showingdetails of construction of the walls of the new and improved barge.

Referring to FIG. 1, the barge of the present invention is generallysymmetrical in overall shape and includes a hull having forward andafter hull portions 10 and 11, v

respectively, and an intermediate hull portion 12. As shown, the hullitself is closed by a deck 13 to define a cargo space which may bedivided by transverse bulkheads 14 and a longitudinal bulkhead 15 (FIG.3), to define a plurality of cargo holds 15a. Access to the cargo spaceis had through hatches 16 (FIG. 2) formed in the deck 13.

In accordance with the principles of the invention, the entire bargestructure is fabricated from plastic panels 17 which act in a dualcapacity as thermal insulators and rigid load bearing structuralmembers. More specifically, and as shown in FIGS. 4 and 5, each of theplastic panels 17 includes a shell 18 of polyester resin reinforced withsuificient fiberglass to impart significant and adequate structuralstrength, which shell is filled with a cellular insulating material,such as polyvinylchloride or polyurethane foam 19. The principal innerand outer shell surfaces are joined and held in spaced relation by aplurality of integral transverse web sections 24. The connecting websections divide the individual panels into a plurality of sections orcells and, in conjunction with the foam material filling the cells,impart significant structural rigidity to the panels. Certain additionaldetails of the panel construction are reflected in my copendingapplication Serial No. 394,287, filed September 3, 1964, for InsulationSystem.

The peripheries 20 of the respective panels 17 are of predeterminedstepped configuration to interlock matingly with one another, inaccordance with the principles of the invention. As illustratedparticularly in FIG. 5, the panel margins advantageously includeperipheral flanges 25 received in corresponding recesses 26 in adjacentpanels. The stepped peripheral configuration of the panels, inconjunction with the flanges 25, provides substantial longitudinally andtransversely oriented surface areas for bonding, to provide aliquid-tight structural sound joint. Special, stepped connecting pieces,such as 3 indicated at 27, 28 in FIG. 3, may be utilized to join panelsat corners and other places of intersection. The construction of theconnecting pieces is of insulating foam material encapsulated in a shellof polyester resin and fiberglass, similar to construction of the panelsthemselves.

The hull walls 22 of the barge, as well as the bulkheads 14, 15 and thedeck 13, are fabricated from groups of contiguously arrayed panels 17united at their peripheries by an interposed epoxy adhesive 21 or thelike (FIG. to form stable, liquid-tight joints 23. In accordance withthe principles of the invention, the completed plastic structure, anavigable barge, is capable of bearing the hydrostatic loads imposed bythe liquefied gas cargoes as well as capable of withstanding the inducedthermal stresses of the cryogenic cargoes.

Alternatively, as found necessary or where desirable, large sections ofthe barge, having a similar fiberglass reinforced polyester shell andurethane foam construction, may be pro-molded, or otherwiseprefabricated, and later joined by a stepped and glued arrangement suchas described hereinabove and in the aforementioned copendingapplication. Such a construction would, of course, significantly reducethe number of joints necessary in a barge of a given size.

It should be appreciated that, in accordance With the principles of thepresent invention, a barge may be constructed with minimum effort andmaterial, since the barge itself functions as a thermally insulatedcontainer. In other words, significant economies in production arerealized, by incorporating the vessel, cargo container, and thermalinsulation into a single autonomous unit rather than having three ormore separate structures.

The new and improved plastic barge is intended primarily for still waterservice, such as in rivers and canals, and is designed to possesssufficient structural integrity for that purpose and, additionally, topossess sufficient thermal insulating properties to prevent the unduewarming and consequent volitalization of liquefied gas cargoes. Thisadvantageous structure is achieved without the use of metallic or likeembrittleable structural members.

It should be understood that the specific mode of construction hereinillustrated and described is intended to be representative only, ascertain changes may be made therein without departing from the clearteachings of the disclosure. Accordingly, reference should be made tothe following appended claims in determining the full scope of theinvention.

What is claimed is:

1. A rigid barge for transporting cyrogenic cargoes at atmosphericpressure comprising (a) a deck portion,

(b) a rigid hull having forward and after portions and intermediatecargo-carrying portions, said cargo carrying portions cooperating withsaid deck portion to define a closed liquid carrying cargo hold,

(0) said hull and deck portion being substantially entirely fabricatedfrom rigid load bearing insulation panels,

(d) said panels being matingly stepped at their peripherres,

(e) said panels also having fiberglass reinforced polyester resin shellsfilled with a suitable insulating foam and a plurality of integraltransverse web sections between the principal inner and outer shellwalls,

(f) said integral web sections being constructed offiberglass-reinforced-polyester and of sufiicient strength to contributeto the overall structural rigidity of said insulation panels.

2. The barge of claim 1 including (a) adhesive means bonding togetheradjacent panels at their matingly stepped edges in an effectivelycontinuous, stable and liquid-tight manner.

3. A rigid barge in accordance with claim 1, in which (a) saidinsulating foam is chosen from the group including polyvinylchloride andpolyurethane.

References Cited by the Examiner UNITED STATES PATENTS 2,023,452 12/1935Voegeli 52-592 X 2,724,358 11/1955 Harris et al. 114-74 X 2,896,2717/1959 Kloote et al. 52-309 X 3,067,712 12/1962 Doerpinghaus 114-743,152,570 10/1964 Dyer 114--69 3,176,055 3/1965 Loos 96 X 3,221,91612/1965 Rysgaard 2209 FERGUS S. MIDDLETON, Primary Examiner. MILTONBUCHLER, Examiner.

T. M. BLIX, Assistant Examiner.

1. RIGID BARGE FOR TRANSPORTING CRYOGENIC CARGOES AT ATMOSPHERICPRESSURE COMPRISING (A) A DECK PORTION, (B) A RIGID HULL HAVING FORWARDAND AFTER PORTIONS AND INTERMEDIATE CARGO-CARRYING PORTIONS, SAID CARGOCARRYING PORTIONS COOPERATING WITH SAID DECK PORTION TO DEFINE A CLOSEDLIQUID CARRYING CARGO HOLD, (C) SAID HULL AND DECK PORTION BEINGSUBSTANTIALLY ENTIRELY FABRICATED FROM RIGID LOAD BEARING INSULATIONPANELS, (D) SAID PANELS BEING MATINGLY STEPPED AT THEIR PERIPHERIES, (E)SAID PANELS ALSO HAVING FIBERGLASS REINFORCING POLYESTER RESIN SHELLSFILLED WITH A SUITABLE INSULATING FOAM AND A PLURALITY OF INTEGRALTRANSVERSE WEB SECTIONS BETWEEN THE PRINCIPAL INNER AND OUTER SHELLWALLS, (F) SAID INTEGRAL WEB SECTIONS BEING CONSTRUCTED OFFIBERGLASS-REINFORCED-POLYESTER AND OF SUFFICIENT STRENGTH TO CONTRIBUTETO THE OVERALL STRUCTURAL RIGIDITY OF SAID INSULATION PANELS.